Hi Patricia, I would stop in Fredericksburg if I needed to stop after about 4-4.5 hours of driving. It's conveniently located on I-95. There's an official Virginia State Welcome Center on I-95, between US17 and SR3, in Fredericksburg - the best place to get travel advice, where to stay, and to pick up useful brochures and maps. It's open daily from 8:30 am to 5 pm. There are a couple of hotels located close to I-95, like:
Definitely you want to plan to stay in Breezewood. There are many Hotels there. I always stay there. You have created a realistic time line for travel from Pittsburgh to Virginia Beach.